Manila: Communist insurgents who seized 39 gold prospectors in the southern Philippines have released all but three of them, authorities said Monday.

Guerrillas of the New People`s Army (NPA) released 36 of the small-scale miners they had abducted on Saturday as government troops closed in on them, said Arturo Uy, the area`s governor.

"They were used as human shields," Uy said, following negotiations that secured the release of most of the captives in the gold-rich Compostela Valley in the Davao region of Mindanao island.

It was not known why the NPA had held onto the remaining three.

The insurgents had seized the miners as the military was conducting a major operation against them in a mountainous area that has over the years attracted thousands of prospectors who operate illegal gold mines.

Entire villages have been set up around such mines, which have also become a lucrative source of extortion money for the rebels, officials have said.

In the nearby town of Asuncion on Sunday, three soldiers were wounded when the NPA set off an explosive device to ambush a patrol, police said.

The Philippines has stepped up operations against the NPA in recent months, capturing three of its senior leaders since March in what has been described by the military as a deadly blow to the movement.

The NPA is the armed wing of the Communist Party of the Philippines, whose rebellion has claimed tens of thousands of lives since 1969.
President Benigno Aquino had hoped to reach a peace deal with the insurgents before his six-year term ends in 2016, but planned peace talks have been hampered by rebel demands that detained comrades be freed.
The capture of the senior leaders has further dimmed the prospect of new talks, analysts have said.